The present invention relates to communication line connection. More specifically, the present invention relates to an improved system and method for attaching a strand of optical fiber to a fiber array substrate.
Several methods exist in the art for attaching optical fiber(s) to a fiber array unit, wherein optical signals are passed to devices such as a waveguide (Array Waveguide Gratings; AWG), planar lightwave circuit (PLC), or variable optical attenuator (VOA), for example, to be channeled to other optical fiber(s) or to be routed to light source(s) and/or light detecting device(s), such as light emitting diode(s) (LED) and photodiode(s), respectively. FIG. 1 illustrates a system for securing an optical fiber 108 to a fiber array substrate 104 as known in the art. The fiber 108 includes a thin glass center core 102 through which the light travels. Also, the fiber 108 contains a cladding 105, which is an optical material surrounding the core 102 to reflect light back into the core 102 (providing the total internal reflection necessary for fiber optic communication). Lastly, an optical fiber typically has a jacket 107 (or buffer coating), which is a plastic coating that protects the fiber from damage and moisture.
Typically, in coupling an optical fiber 108 to a substrate 104, a portion of the fiber 108 not containing the jacket 107 (only the core 102 and cladding 105) is placed in a ‘V’-shaped groove 112 in the top of a portion of the substrate 104 to hold the optical fiber in correct alignment. Next, a lid made of glass (“lid glass”) 101 is secured to the substrate 104 by an adhesive, such as ultraviolet-cured (UV) epoxy. Next, a portion of the optical fiber 108 covered by the jacket 107 (enclosing cladding 105 and core 102) is secured to the substrate by an adhesive 106, such as UV epoxy.
FIG. 2 illustrates one problem associated with this method of securing an optical cable 108 to a substrate 104. A susceptibility to coupling failure exists under physical loading of the optical fiber 208. The jacket 207, which is typically plastic is capable of deformation under stress, such as tensile force 210, is applied to the optical fiber 208. This jacket deformation causes the critical point of coupling to be between the jacket 207 and the cladding 212, where slippage is very likely. Slippage between cladding 212 and jacket 207 can greatly reduce the strength of the coupling between the optical cable 208 and the substrate 214. It is difficult to increase the clamping force upon the optical fiber 208 between the substrate 214 and lid glass 216 without damaging the fiber 208.
It is therefore desirable to have an improved system and method for attaching an optical fiber to a fiber array substrate, which avoids the aforementioned problems, as well as providing other advantages over the prior art.